The Gnumeric Manual
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# 13.2. Goal Seek Tool

Use Goal Seek Tool to search for a value of a single model variable that yields a given desired value of another single variable. For example, you can use the Goal Seek to find the break-even value for sales (the break-even is the amount of sales whose marginal revenue just covers the fixed costs and the profit is thus zero).

## 13.2.1. Using the Tool

First, select the ``Goal Seek...'' tool item from ``Tools'' menu. Specify the output variable cell (``Set Cell'') by typing the cell reference into the entry or by clicking the worksheet cell. If you are searching for the break-even point, for example, you should specify the cell reference of the profit calculation here.

Specify the desired result for the output variable cell into the ``To Value'' cell. In the search for the break-even, specify this to be zero.

Specify the input variable cell (``By changing cell'') by typing the cell reference into the entry or by clicking the worksheet cell. In the search for the break-even, specify the cell reference of the sales here. When you have done this, you may want to press the ``Apply'' button to start the tool.

## 13.2.2. Results

Gnumeric will systematically iterate the model by changing the input value to achieve the desired result, if possible. If goal seek was successful the tool displays the message ``Goal Seeking with cell __ found a solution''.

It is possible that Gnumeric does not find a solution that generates the desired result. There may not be such a solution for the model, or, it may be too difficult to find. For example, the mathematical function behind the calculation may have many non-continuous points.

## 13.2.3. Desired Value in a Given Range

If Gnumeric did not find a solution that generates the desired result, you may want to try to specify a range (minimum and maximum) in which the value of the output variable should be. To do this, specify the ``Minimum'' and ``Maximum'' entries.

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